diff --git a/perf/BenchmarkApp/PerformanceTest.Client/PerformanceTestRunningContext.cs b/perf/BenchmarkApp/PerformanceTest.Client/PerformanceTestRunningContext.cs
index dcd0f1674..baa9eaf6e 100644
--- a/perf/BenchmarkApp/PerformanceTest.Client/PerformanceTestRunningContext.cs
+++ b/perf/BenchmarkApp/PerformanceTest.Client/PerformanceTestRunningContext.cs
@@ -5,12 +5,14 @@ public class PerformanceTestRunningContext
     int count;
     bool isRunning;
     Stopwatch stopwatch;
-    List<List<double>> latencyPerConnection = [];
-    List<object> locks = [];
+    List<List<double>> latencyPerConnection;
+    List<object> locks;
 
     public PerformanceTestRunningContext(int connectionCount)
     {
         stopwatch = new Stopwatch();
+        latencyPerConnection = new (connectionCount);
+        locks = new (connectionCount);
         for (var i = 0; i < connectionCount; i++)
         {
             latencyPerConnection.Add([]);
@@ -49,6 +51,8 @@ public void Complete()
     public PerformanceResult GetResult()
     {
         var latency = MeasureLatency();
+        latencyPerConnection.Clear();
+        locks.Clear();
         return new PerformanceResult(count, count / (double)stopwatch.Elapsed.TotalSeconds, stopwatch.Elapsed, latency);
 
         Latency MeasureLatency()
@@ -66,7 +70,7 @@ Latency MeasureLatency()
                 latencyPerConnection[i].Sort();
             }
             var latencyMean = (totalCount != 0) ? totalSum / totalCount : totalSum;
-            var latencyAllConnection = new List<double>();
+            var latencyAllConnection = new List<double>(totalCount);
             foreach (var connections in latencyPerConnection) latencyAllConnection.AddRange(connections);
             var latency50p = GetPercentile(50, latencyAllConnection);
             var latency75p = GetPercentile(75, latencyAllConnection);
diff --git a/perf/BenchmarkApp/PerformanceTest.Client/Program.cs b/perf/BenchmarkApp/PerformanceTest.Client/Program.cs
index 1607b8066..574a74de1 100644
--- a/perf/BenchmarkApp/PerformanceTest.Client/Program.cs
+++ b/perf/BenchmarkApp/PerformanceTest.Client/Program.cs
@@ -79,7 +79,7 @@ async Task Main(
             }
             var result = await RunScenarioAsync(scenario2, config, controlServiceClient);
             results.Add(result);
-            datadog.PutClientBenchmarkMetrics(scenario.ToString(), ApplicationInformation.Current, serialization.ToString(), result);
+            await datadog.PutClientBenchmarkMetricsAsync(scenario.ToString(), ApplicationInformation.Current, serialization.ToString(), result);
         }
     }
 
@@ -136,8 +136,6 @@ async Task Main(
             writer.WriteLine($"{s}\t{string.Join("\t", results.Select(x => x.RequestsPerSecond.ToString("0.000")))}\t{results.Average(x => x.RequestsPerSecond):0.000}");
         }
     }
-
-    await datadog.WaitSaveAsync();
 }
 
 async Task<PerformanceResult> RunScenarioAsync(ScenarioType scenario, ScenarioConfiguration config, IPerfTestControlService controlService)
@@ -265,7 +263,7 @@ public static class DatadogMetricsRecorderExtensions
     /// <param name="applicationInfo"></param>
     /// <param name="serialization"></param>
     /// <param name="result"></param>
-    public static void PutClientBenchmarkMetrics(this DatadogMetricsRecorder recorder, string scenario, ApplicationInformation applicationInfo, string serialization, PerformanceResult result)
+    public static async Task PutClientBenchmarkMetricsAsync(this DatadogMetricsRecorder recorder, string scenario, ApplicationInformation applicationInfo, string serialization, PerformanceResult result)
     {
         var tags = MetricsTagCache.Get((scenario, applicationInfo, serialization), static x => [$"app:MagicOnion", $"magiconion_version:{x.applicationInfo.MagicOnionVersion}", $"grpcdotnet_version:{x.applicationInfo.GrpcNetVersion}", $"messagepack_version:{x.applicationInfo.MessagePackVersion}", $"memorypack_version:{x.applicationInfo.MemoryPackVersion}", $"process_arch:{x.applicationInfo.ProcessArchitecture}", $"process_count:{x.applicationInfo.ProcessorCount}", $"scenario:{x.scenario}", $"serialization:{x.serialization}"]);
 
@@ -279,6 +277,9 @@ public static void PutClientBenchmarkMetrics(this DatadogMetricsRecorder recorde
         recorder.Record(recorder.SendAsync("benchmark.client.latency_p75", result.Latency.P75, DatadogMetricsType.Gauge, tags, "millisecond"));
         recorder.Record(recorder.SendAsync("benchmark.client.latency_p90", result.Latency.P90, DatadogMetricsType.Gauge, tags, "millisecond"));
         recorder.Record(recorder.SendAsync("benchmark.client.latency_p99", result.Latency.P99, DatadogMetricsType.Gauge, tags, "millisecond"));
+
+        // wait until send complete
+        await recorder.WaitSaveAsync();
     }
 }
 
diff --git a/perf/BenchmarkApp/PerformanceTest.Client/StreamingHubScenario.cs b/perf/BenchmarkApp/PerformanceTest.Client/StreamingHubScenario.cs
index 7b3670a18..dab7fc91e 100644
--- a/perf/BenchmarkApp/PerformanceTest.Client/StreamingHubScenario.cs
+++ b/perf/BenchmarkApp/PerformanceTest.Client/StreamingHubScenario.cs
@@ -6,21 +6,20 @@ public class StreamingHubScenario : IScenario, IPerfTestHubReceiver
 {
     IPerfTestHub client = default!;
     readonly TimeProvider timeProvider = TimeProvider.System;
-    long beginTimeStamp = default;
 
     public async ValueTask PrepareAsync(GrpcChannel channel)
     {
         this.client = await StreamingHubClient.ConnectAsync<IPerfTestHub, IPerfTestHubReceiver>(channel, this);
-        this.beginTimeStamp = timeProvider.GetTimestamp();
     }
 
     public async ValueTask RunAsync(int connectionId, PerformanceTestRunningContext ctx, CancellationToken cancellationToken)
     {
         while (!cancellationToken.IsCancellationRequested)
         {
+            var begin = timeProvider.GetTimestamp();
             await client.CallMethodAsync("FooBarBaz🚀こんにちは世界", 123, 4567, 891011);
             ctx.Increment();
-            ctx.Latency(connectionId, timeProvider.GetElapsedTime(this.beginTimeStamp));
+            ctx.Latency(connectionId, timeProvider.GetElapsedTime(begin));
         }
     }
 }